Elastomeric strip for vertical pavement joints



J. E. CARTER Jan. 25, 1955 ELASTOMERIC STRIP FOR VERTICAL PAVEMENT JOINTS s shets-sheet 1 Filed May 18, 1946 Fig. I

- INVENTOR. John E. Lahsr BY HIS ATTORNEYS 1955 J. E. CARTER 2,700,329

ELASTOMERIC STRIP FOR VERTICAL PAVEMENT JOINTS Filed May 18, 1-946 3 Sheets-Sheet 2 INVENTOR. Fig.9 John E. Ca rier sy/fzwfymxw HIS ATTORNEYfi 1955 J. E. CARTER 2,700,329

ELASTOMERIC STRIP FOR VERTICAL PAVEMENT JOINTS Filed May 18, 1946 3 Sheets-Sheet 3 my. 17 .16 Fi .1?

INVENTOR.

Fi q. 1.9 John E. Larfer S A TTORNE Y6 ELASTGMERIC STRIP FOR VERTICAL PAVE- MENT .IGINTS John E. Carter, Columbus, Ohio Application May 18, 1946, Serial No. 670,793

12 Claims. (Cl. 94-48) This invention relates to an elastomeric strip for vertical pavement joints, and more particularly pertains to such a strip having sealed air pockets therein, having means for tying-in said strip to concrete pavement cast thereabout, and having means for cooperating with dowel bars for forming a water-proof, compressible, dowel bar vertical joint between adjacent concrete slabs.

in the heretofore known art of concrete slab pavement construction, a particular point of trouble has been in regard to water seepage in the vertical joints between adjacent concrete slabs, which water tends to erode the roadbed, and in cold weather, to freeze causing fragmentation of the concrete. Such water seepage also affects the chiciency of dowel bar action. Dowel bars are universally used to connect adjacent slabs of concrete pavement to prevent relative tilting thereof. Of the various means heretofore known, for filling vertical joints between adjacent concrete slabs, all have been deficient in one form or another under various conditions. For instance, the most commonly used vertical joint filler is bituminous material which is melted and poured into the joints after the concrete has set.

Bituminous material, being relatively plastic over the rangeof temperatures met with in ordinary climates, will permit the concrete slabs to expand during hot periods, but under pressure, exerted by the expanding 'slabs, it is forced out at the top of the joints to form ridges on the road, where it is subjected to contamination and deterioration by the passing of traflic thereover. Such protrusion of the bituminous material is due to the fact that it is imcompressible. The formation of these of bituminous material ridges on the surface of the pavement, 4 during hot weather, causes the jolting of vehicles passing thereover, until the ridge has been mangled and flattened by the Weight of'such traffic. During this process, dust,

- dirt and other debris is ground into the bituminous material causing it to lose its plastic characteristics, and it is graduallyground away and separatedfrom the joints. Upon subsequent contraction of the concrete, which widens the joints, cracks are formed betweenthe concrete and the reduced'amount of filler therein, because said bituminous material is not elasticanddoes not of itself resume the shape in which it was first cast into the joints. The consequence is, thatwater seeps into the cracks and erodes the roadbed, or, if the weather isbelow freezing,

said water freezes andcausesice rupturing of the concrete at such joints. Such deterioration of the pavement becomes progressively worse and causes constant maintenance and refilling of the joints to prevent complete destruction of the road. This item of maintenance is the chief one in the total cost of keeping concrete roads in repair and, until my invention, no completely satisfactory substitute for bituminous material has been found. An

attempt has-been made in recent years to 'fill these vertical joints between concrete slabs with resiliently vulcanized rubber strips anchored in one'way or another in the joints.

it is a well'kn'own fact that rubber even though it be resilient is incompressible. Because of the incompressibility, even though the sealing strips made thereof be resilient and disto'rtable, When the concrete slabs between which such a'strip is placed expand, and thusreduce the size .of' the joints, the rubber is distorted vertically and causes r dgesto protrude from the top of the joints where passing traflic can scuff and cause a wearing-away of such "protruded part of the rubber.

Moreover, such protrudingpart of the rubber. is subject to-horizontal forces, as

trafiic passes over intending to rip; it from the joints, leaving the oints unprotected-against the entry of water.

2,700,329 Patented Jan. 25, 1955 -I have provided an .elastomeric strip, made of rubber, or rubber-like material which is water-proof, and compressible. The compressibility'of my strips is gained by providing-therein anumber of air pockets which, though the elastomeric material itself is not compressible, are compressible because of the natural compressible characterist-ics of .the enclosed air. The air pockets or channels within the strip are totally enclosed-therein so that they do not interfere with the normal outlines of the strip'in producing the water-tight seal against'the concrete or metal sides of the joint-with which they are in abutment. By

-elastomeric material I mean such material as natural rubber which may be distorted,by applied forces, to as muchas 100% of its ordinary dimensions and which, when .tially to its original form.

such distorting forces are removed, will return substan- Ihave, therefore, combined the characteristics ofawater-proof elastomeric material with the advantages of a compressible gas containedztherein, into asingle strip, so that, when said strip is squeezed vby the compressive forcescaused by expansion of the slabs, the strip will not be. caused to distort-in a vertical direction and protrude upon the surface of the road. By such means which I provide, the joint is kept permanently water-proof, noridges are formed on the-road during hot weather, and the joint sealing means is not subject to tralfic wear. I have also provided means whereby dowel bar unitsflmay pass through my elastomeric strip andbe pounding.

"for the dowel .bars. ofso c'alledsynthetic elastomers, which have equivalent wate1'-proofedly connected thereto, the dowel bars ofsuch units each being encased in water-proof casings. I- have furtherprovidedm themeans'for sealing the dowel bar units .throughsaid elastomericstrip, means whereby said encased dowel bars in addition to being-sealed against the entryof water, have a. floating action in the casings in which they .arefheld. Moreover, as a further'safeguard against the .protrusionof my novelelastomeric strips from "the roadbed, I have provided a concavity along the length of their upper edgesso. that .anyv slight tendency of the .cementing a sealing strip ofelastomeric material over any .cutin a strip which is necessary for the fittingof a:strip to the road width'or length.

' Of the-elastomeric materials, which I desire to .usein connection with .my inventiorn, those having the characteristics of being impervious to water, tough resilience,

resistance to atmospheric deterioration, resistance .to oil, resistance to aging and oxidation, and of relatively high tensile strength. Of such materials, I prefer natural rubber vulcanized to that degree of resiliency. and toughness associated with modernautomobile tires, and, to, that end, toughening, aging and vulcanizing ingredients areto be included with the 'raw elastomeric materialin its com- Of the synthetic rubber-like.materials paralleling natural rubber in characteristics, I prefertheoil resistant types of which the butadiene-acrylonitrile copolymersare representative, because such materials resist better the swelling and disintegration .to which .the

'elastomeric strips may be subjectedin situ from oil dripping from passing motor traflic and from lubricants used I realize that there are a number characteristics to natural rubber,.in addition to the buta- .diene-acrylonitrile copolymers, and I include suchin'the classes'of suitable materials. for my novel jointsealing strips.

Therefore, the principal object of my invention is to provide an elastomeric and compressible joint sealing strip for'use in vertical joints between adjacent concrete slabs of a road pavement.

Another object of my invention is to provide such a stripmade vof rubber or rubber-like materials having the characteristics of resilient toughness and water resistance,

which are comparable tothe present day. automobile'tire rubber.

Another object of my invention is to provide an elastomeric strip for use in vertical road joints, between concrete slabs, which strip has sealed therein a number of air pockets so that horizontal compression upon such strip will not cause it to distort in a vertical direction to any extent.

Another object of my invention is to provide such an elastomeric strip which has means for mechanically tying itself into concrete cast thereabout, in a water sealing manner.

Another object of the invention is to provide such a strip with means for sealing the same to encased floating dowel bars which are embedded in the concrete slabs across said vertical joints.

Further objects, and objects relating to details and economies of operation, will definitely appear from the detailed description to follow. In one instance, I have accomplished the objects of my invention by the devices and means set forth in the following specifications. My invention is clearly defined and pointed out in the appended claims. Structure constituting preferred embodiments of my invention .are illustrated in the accompanying drawings forming a part of the specification, in which:

Fig. 1 is a plan view of a concrete slab road pavement showing my novel joint sealing strip and dowel bar construction cooperating therewith.

Fig. 2 is a vertical sectional view of the concrete slab road of Fig. 1, on the line 2-2, showing the dowel bar supporting means.

Fig. 3 is a vertical sectional view through the concrete slab road of Fig. 1 across the joint on the line 3-3, and through the dowel bar unit cooperating therewith.

Fig. 4 is a perspective view of my novel joint sealing strip, indicating both an end and a section portion thereof.

Fifg. 5 is a detail of a dowel bar chair on the vertical section 5-5 of Fig. 1.

Fig. 6 is a sectional view through an elastomeric union for joining the casings of a dowel bar unit which cooperates with the elastomeric strip for water-proofing the connection.

7 is a perspective view of the union shown in Fig. 8 is a perspective showing of a U-shaped chair for holding my vertical strip upright on the roadbed before the pouring of concrete thereover.

Fig. 9 shows a sample of a staple used for fastening the chair unit of Fig. 5 to the roadbed.

Fig. 10 is a representation of a brace wire used in the frame work supporting my dowel bars and vertical joint sealing strips.

Fig. 11 shows sideplates for supporting the elastomeric strip, between the chairs, in a vertical manner, prior to the pouring of the concrete, said plates having dowel bar apertures therein.

Fig. 12 shows a water-proof dowel bar casing for one end of a dowel bar.

Fig. 13 shows a dowel bar.

Fig. 14 shows the seal for sealing a cut end of my vertical joint sealing strip.

Fig. 15 is a vertical section through my novel strip with the sealing piece cemented thereto.

Fig. 16 is a side elevation view of the end seal for a cut sealing strip.

Fig. 17 is another vertical view of the end seal for the sealing strip.

Fig. 18 is a sectional view on the line 18-18 of Fig. 17.

Fig. 19 is a view of an elastomeric sleeve for covering 7 the union, shown in Fig. 6 and in Fig. 7, to form between it and the elastomeric strip a snug watertight fit.

In the'drawings, the same reference numerals refer to the same parts throughout the several views, and the sectional views are taken looking in the direction of the arrows at the ends of the section lines.

Referring to Fig. 4, my novel joint sealing strip, made of the specified elastomeric, resilient, and tough material has a bottom edge 20 which rests on the roadbed, side faces 21 and 22 against which the compression forces of the expanding concrete slabs are directed, and a top edge 23 which shows from the surface of the concrete road as the top edge of said vertical strip. At intervals, a distance apart, as is necessary for the strength of the construction wanted, are dowel bar apertures 24, piercing the thickness of the strip. Running parallel with the length of the strip near its top edge, and associated with face 21, is a bead 25 connected to the body of the strip by neck 26.

Associated with the face 22, is a similar bead 27 connected to the body of the strip by a neck 28. The beads 25 and 27 are located near the top of the strip, and are two or more times in diameter the thickness of the neck which joins the associated bead to the strip. Referring to Fig. 3 the strip is shown in position after the concrete slabs 3b and 31 are poured to a height of the top edge 23, encasing the beads 25 and 27, thus mechanically bonding the strip to the concrete.

Referring again to Fig. 4, running parallel through the length of the strip are air channels, such as channels 32 and 33, which form continuous air passages from one end of the strip to the other. The channels in said strips, preferably, are parallel and fit close together so as to provide a maximum volume of air within the strip. It will also be observed that channels 32 and 33 are shaped in cross sections in such a manner that side pressure exerted on sides 21 and 22 will tend to collapse said channels so that the inter-channel webs between them will fold without horizontal resistance. That is, the webs between the channels are formed so that the compression forces of the expanding concrete, directed against the side faces of the strip, will not meet with any resistance of consequence because of said inter-channel webs.

By examination of Figs. 3 and 4, it will be seen that the top edge of the strip is slightly concave in cross section so that, when compression forces operate against the sides of the strip, any slight distortion upwardly of the strip will spend itself by forcing out the concavity of the top edge so that the rubber will not protrude above the concrete surface level.

As will be described, the end of the air channels are sealed, and the air channels exposed by the dowel bar apertures such as aperture 24 are sealed, against the entry of water and against the expulsion of air so that there will be no pumping action during the compression and decompression of the strips which tends to draw water into the assembly. In other words, the strip after being assembled in the road is sealed air-tight and watertight, so that the compressibility of the air in the air channels creates sufficient force outwardly to cause the elastomeric strip to form a perfect water-tight seal with the concrete and the side plates, as will be explained.

Referring to Figs. l4, 15, 16, 17 and 18, there is shown a means for sealing the cut ends of a strip. Ordinarily, in producing such a strip as shown in Fig. 4, extrusion molding is used, and the strip comes in undefined lengths. In order to fit such a strip to a roadbed under construction, it is obvious that the strips must be cut to size, and this necessitates cutting through the air channels at right angles as shown in Fig. 4. In Fig. 16, there is shown a seal which is formed with shaped plugs to fit the channel apertures. For instance, in Fig. 17 looking at such a seal strip into the face of the plugs, plug 40 is shaped to fit aperture 40a, Fig. 4, and plug 41 is adapted to fit aperture 41a, Fig. 4. It will be observed that each of the plugs has, in the center thereof, a hole to render the plugs collapsible to fit within its correspond ing aperture, such a hole being shown at 42, Fig. 17. Cement, or other fastening means, is used to fasten such seals on the cut end of the joint sealing strip in a waterproof manner to form a water-tight and air-tight end to the strip. Thus, referring to Fig. 14 the seal strip 43 is shown fastened to the end of the elastomeric vertical joint sealing strip. For convenience, the seal need extend no higher than the beads as the top air channel need not be protected from entry of water inasmuch as it ordinarily extends above the berm of the road and will drain. Fig. 15 is a vertical section through a strip with the end seal in place, showing how the plugged channels are physically strengthened by their cooperation. Fig. 18 is a section through Fig. 17 on the line 1818 showing the hole 42b and the plug 41b, in an enlarged manner.

Coming now to describe the installation of the strip upon the roadbed prior to pouring the concrete, reference is made to Fig. 3 in which a roadbed 50 is shown with the vertical elastomeric sealing strip placed thereon. Bordering each vertical face of the sealing strip is a metal face plate 51 (see Fig. 11) having therein, at intervals, apertures, like aperture 52, which are aligned with the apertures, like aperture 24 (see Fig. 4) of the strip, so that dowel bars may be passed therethrough. At intervals corresponding to the intervals at which the dowel bars pass through, are U-shaped chairs 53 (see also Fig. 8) braced by braces 54 welded thereto, and fastened, as will aaomsae be-described, to the roadbed,;in -,a vertical;,position,n so as to receive, as shown in Fig.3, the sealing ;,strip,;1and the side plates, in the U-shaped portion-ofsaid chairs. The side plates are :held against the sides of the sealing strip ina water-tight manner by the chairs.

A dowel bar unit is associated with each dowel bar aperture. Each dowel bar unit includes a dowel bar 55 (Fig..13) having a helical, lubricating groove 56, a casing 57 (Fig. 12) for each end of the dowel bar, each casing beingwater-proof except for a dowel bar-receiving aperture opening atone end (see Fig. 3), and an elastomericwater-proof union 60;(Figs. 6 and 7) joining the casings associated with a dowel bar by engaging grooves 58'on the inner ends thereof. The union 60 is formed with compression pleats 8% (Fig. 6) so that the casings may move together overthe encased dowel bar. The casings 57 (Fig. 12) are formed with'a groove 59on the outer end to receive chairs .as will be described. A lubricating reservoir 61 ,(Fig. 3) is provided in the interior dowel aperture to hold lubricant which works along the groove .56 of the dowel bar as the casings move with respect to the dowel bar. The dowel bar unit assembly to the strip. is best shown in Fig. 3. An -elastomeric water-proof sleeve 65 (Fig. 19,) is fitted over the union (see Fig. 3) to act as a water seal between the dowel bar unit aperture in the strip and the rubber union. It will be apparent that in assembling the joint structure on the road, that witha dowel barunit assembled together by the union and sealed by the sleeve 65,. it is only necessary to pass the same through a dowel bar 'unit aperture 52 or" the side plates and the corresponding aperture 24. of the vertical sealing strips to a point where the sleeve is snugly in the aperture.

To support the dowel bar units, such as shown in Fig. 3, before the concrete is cast, chairs like chair 66 (Fig. 5), having downwardly extending legs 67 and 68, joined by a bottom piece 69, stapled to the roadbed by staples 70 and 71 '(see also Fig. 9), are provided for each end of the dowel bar unit. A downwardly extending loopin the upper portion of .the chair engages the circumferential groove 59 of the outer end of the dowel bar casing so as to support it at a definite distance above the road-bed level. As shown in Fig. 3, the strip supporting chair 53 is welded to the associated dowel bar unit chairs 66 at points like point 70. The strip supporting chair and the dowel bar supporting chairs of a dowel bar unit thereby are welded together intoa solid supporting structure. The dowel bar units along a strip are further supported by a rod like red 75 (Fig. andFig. 5), welded to all the dowel bar chairs onan associated side of the strip.

The novel beading by which the top of the stripis mechanically tied intonthe concrete, after it is cast thereover, is far superior to any such mechanical bond previously known. The elastomeric quality of the sealing strip permits contraction of the concrete for a considerable extent beyond'normalwithout stretching of the necks 26 and 28 suflic'iently .tocause the beads and 27 to be withdrawn through the narrow aperture occupied by the stretched necks.

By referring to the construction shown in Fig. 3, by which the dowel barunit .isconnected to the vertical sealing strip unit, it will be understood that upon compression movement of the concrete slabs and 31 toward one another, during periods of their expansion, the rubber strip will.be compressedas also willbe the air in the channels contained therein. At the same time, the easings 57 held embedded in the concrete will push toward one another, and the formation 80, (Fig. 6), in the rubber union joining the casings, will permit of such movement of the casings together, leaving the dowel bar floating freely within the casings and rubber union, without effect as to its load transferring and tilt preventing characteristics.

My Patent 2,508,443, issued May 23, 1950, is directed to a novel dowel assembly having a sectional sleeve interposed between the two casings, each of which is interlocked with a section of the sleeve.

I am aware that the device disclosed herein may be varied considerably without departing from the spirit of my invention and therefore, I claim my invention broadly as indicated by appended claims.

Having thus described my invention, what I desire to claim as new and useful is:

1. A joint sealing strip for use in concrete slab road construction, comprising a strip of water-proof elastomeric-, material having;side faces, along its length, said --strip beingprovided witha plurality of sealed air channels parallel one another and separated by webs therebetween, the webs between said channels beingangularly posi- 'tioned with reference to the side faces of the strip, so

that said strips may be compressed by lateral pressure upon the sides of the strip with a minimum of resistance oifered by said webs, a dowel bar aperture cut at intervals through the thickness of the strip and through some of said channels, and a resilient sleeve inserted inthe apertures for sealing the channels.

2. A joint sealing strip for use .in concrete slab road construction, comprising a long strip of water-proof tough and resilient elastomeric material having wide: side faces along its length, said strip having sealed air channels provided along its length between the long edges of the stripandseparated by thin'V-shaped webs so that when the strip is compressed by forces pressing inwardly on the faces thereof on either side, said strip will be compressed, compressing the air contained in said channels, without any great resistance from said webs which fold into pleats, a dowel bar aperture cut at intervals through the thicknessof the strip and through .some of the channels, and a resilient elastomeric sleeve inserted in the apertures for's'ealing the channels.

3. A joint sealing strip for use in sealing vertical joints in concrete slab road construction comprising a strip of water-proof resilientelastometric material, having a plurality of sealed internal air channels provided between the top and bottom edges, substantially throughout the body of the strip, separated by webs, the webs between said-air chaimels being-formed in V-shapes, with the point "of the V pointed either upwardly or downwardly, so 'that side forces tending to compress the strip will not be greatly resisted-by said webs, a dowel bar aperture 'cut at intervals through the thickness of the strip and some of said channels, and a resilient seal lining the apertures.

4. 'A joint sea-ling-rstrip for use in making a cast concrete-slab pavement on a roadbed, comprising a flatstrip of elastomeric material, s'aidstrip having a plurality-of internal channels separated by narrow webs andsaid striphaving .integraltherewith a round bead running the length of the strip on each-side thereof,,each bead being connected to the strip by a neck-like portion, saidbead being incross section atleast two times the thickness of the associated neck, saidbead being adapted to be embedded in the concrete of the slabs on the associated side of the joint, a dowel bar aperture cut atintervals'through the thickness of thestrip and through some of the channels, and a resilient sleeve inserted in the aperturesfor sealing the channels.

5. A joint sealing strip unit for use in making a cast concrete slab pavement on a roadbed, comprising a joint filling portion shaped to fill an intended joint and a bead portion on. each side integral with the joint filling portion, said beads being extended laterally from-the side of the joint filling portion toward the concrete on*the sides of the joint, said beads being approximately circular in cross section except for a neck-like portion with which the bead is joined to the joint filling portion, said beads being at least two times the thickness of the associated neck portions, said joint sealing strip units being made, of velastomeric material, and said jointsealing porof the unit having air channels internally thereof, which channels are sealed against the entry of -water,,and a. dowel bar aperture out through the strip and some of the air channels and having its surrounding walls sealed to close said channels.

6. A joint sealing strip for use in making a cast concrete slab pavement on a roadbed, said strip being adapted to be place on the roadbed prior to the casting of concrete thereabout, and said strip being adapted to cooperate with dowel bars passing therethrough, comprising a length of elastomeric material having at intervals along its length between its top and bottom edges, dowel bar apertures with their walls sealed to enclose the internal structure of said strip, and having internally thereof, along its length, air channels, and having projecting laterally, on each side the length thereof, near the top of the strip but below the intended top surface of the concrete to be cast thereabout, a bead joined to the strip by a narrow neck, whereby when said concrete is cast thereabout it forms a mechanical bond therewith;

7. A joint sealing strip for use in making a cast concrete slab pavement on a roadbed, said strip being adapted to be placed on said roadbed before concrete is cast thereabout, and said strip being adapted to have dowel bars passed therethrough, comprising a length of elastomeric material pierced at intervals, between its top and bottom edges, to receive dowel bars therethrougli, said strip having, internally thereof and lengthwise of the strip, a plurality of enclosed air channels, including those pierced by the dowel apertures, whereby when said strip is placed on the edge on the intended roadbed and the concrete is cast thereabout it forms a water-proof resilient and compressible joint filler.

8. A joint sealing unit for use in placement on a roadbed, before concrete is cast thereabout to form a slab concrete road pavement, including in combination, a length of elastomeric joint filler material having a plurality of parallel air channels, running internally thereof the length of the strip and separated from each other by thin webs of material set at angles which give low resistance to compression forces acting laterally against the sides of said strip and having dowel bar apertures through its thickness and some of the channels with the surrounding walls of said apertures sealed to close the channels, and said strip having running lengthwise thereof, on either side near one lengthwise edge, laterally extending portions consisting of a bead joined to the main body of the strip by relatively narrow neck, said beads and necks being adapted to be embedded in concrete cast thereabout and to form a mechanical bond therewith when said concrete is set; a metal plate running the length of said strip on either side thereof below the bead, said plates being relatively thin compared to the thickness of the strip; a dowel bar extending through the metal plate and the dowel apertures of the strip, a metal chair supporting said strip, dowel bar and plates on said roadbed at the intended joint, whereby, when concrete is cast thereabout, said strip forms a resilient compressible joint filler which is water-proof, and which joint filler strip is, by means of the beads and necks thereof, mechanically bonded into the concrete, to render said joint water-proof on contraction of said concrete.

9. A joint filler strip and dowel bar unit construction for use on a roadbed prior to the casting of concrete thereabout to form a concrete slab road pavement, in-

cluding in combination, an elastomeric and compressible vertical joint sealing strip having along its median line, the length thereof, dowel bar apertures, at intervals, for receiving dowel bar units; and a dowel bar unit piercing each of said apertures, each of said dowel bar units including a dowel bar, a casing for either end of the dowel bar, said casings being waterproof except for the meeting edges of said casings, and said meeting edges of the casings being joined in a water-proof connection by an elastomeric water-proof union, and said elastomeric union being fitted with a water-proof fitted elastomeric sleeve which snugly fits into said dowel bar apertures to seal them.

10. A joint filler strip, adapted to be placed on a roadbed prior to the casting of concrete thereabout to form a concrete slab road pavement, said strip being made of resilient elastomeric material and having, along the median line of its length, a dowel bar aperture at intervals, said strip having internally thereof along its length a plurality of parallel air channels, said air channels being cut by said apertures, and an elastomeric sleeve fitting into said apertures to seal said air channels against the entry of water, and said strip having integral therewith formed portions for mechanically bonding it to concrete cast thereabout.

11. A joint sealing unit for use in cast concrete slab road pavement, which unit is adapted to form a framework around which concrete may be poured to form concrete slabs connected by dowel bars which pass through the joint, including in combination, a strip of toughly resilient elastomeric material having top and bottom edges and side faces, having along its median line, in the lengthwise direction thereof, dowel bar apertures piercing said strip from face to face, and having extending from each face near the top edge and running the length of the strip a rounded bead made integral with the strip by a relatively narrow neck portion, the axis of the said beads running parallel with the length of the strip; and a dowel bar unit piercing each hole, said dowel bar units each consisting of a dowel bar, a half casing fitting over each end of the dowel bar, said casings meeting towards the middle of said dowel bar, an elastomeric water-proof union tying said casings together so that said dowel bar is encased entirely against the entry of water; and a rubber sleeve covering said union in a water-tight manner and being of a dimension to fit water-proofedly in the associated aperture of the strip, each of said dowel bar units being fitted by means of said seal into the strip.

12. A paving joint construction comprising concrete slabs spaced apart to provide a space therebetween, a strip of waterproof elastomeric material interposed to fill the space between the slab, said strip having a plurality of narrowly spaced air channels extending substantially throughout its body to provide air channels throughout the height of the joint space and having dowel bar apertures through its thickness and some of the channels, and means for sealing the end of the channels, including that through which the dowel apertures extend, to prevent a fluid being pumped through the paving construction during the compression of the strip and the contraction and expansion of the pavement.

References Cited in the file of this patent UNITED STATES PATENTS 1,628,090 Weiss May 10, 1927 1,723,306 Sipe Aug. 6, 1929 2,041,961 Robertson May 26, 1936 2,042,524 Hall et al June 2, 1936 2,065,522 Fischer Dec. 29, 1936 2,071,299 Gammeter Feb. 16, 1937 2,082,977 Robertson June 8, 1937 2,095,060 Geyer Oct. 5, 1937 2,095,061 Geyer Oct. 5, 1937 2,101,883 Warner Dec. 14, 1937 2,103,003 Fischer Dec. 21, 1937 2,111,113 Fischer Mar. 15, 1938 2,139,851 Roberts Dec. 13, 1938 2,156,681 Dewhirst et al. May 2, 1939 2,181,623 Klein Nov. 18, 1939 2,197,786 Capouch Apr. 23, 1940 2,224,148 Fischer Dec. 10, 1940 2,227,614 Willard Jan. 7, 1941 2,400,493 Fischer May 21, 1946 2,431,385 Fischer Nov. 25, 1947 2,482,836 Brickman et a1. Sept. 27, 1949 2,508,443 Carter May 23, 1950 

